1. Field of the Invention
The present invention relates to a light emitting device package and a method of manufacturing the same.
2. Description of the Related Art
A light emitting diode (LED) is a semiconductor device capable of emitting light of various colors, due to electron-hole recombination occurring at a p-n junction when a current is supplied thereto, by using compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaN, AlGaInP and the like as a light source.
LEDs are environmentally-friendly, have fast response rates on the level of several nano seconds so as to be effective for a video signal stream, and are capable of being impulsively driven.
Moreover, LEDs have a color gamut of 100% or higher and the luminance and color temperature thereof may be easily adjusted according to the amount of light emitted from red, green and blue LEDs. Therefore, LEDs have been actively employed as light emitting devices in various types of light emitting apparatuses.
Particularly, of late, LEDs using nitride-based semiconductors are employed as white light sources, so they are widely applied in various fields requiring white light sources such as in the case of a keypad, a backlight, a traffic light, airport runway lights, a general lighting apparatus and the like.
The factors determining the characteristics of LEDs are color, light speed, distribution of luminous intensity, and the like.
These characteristics are primarily determined by compound semiconductor materials used in LEDs, and are secondarily affected by a package structure and a phosphor applying method.
In recent years, the primary characteristics of an LED chip itself have been rapidly enhanced, but at present, the development thereof has reached a certain level and the pace of development is slowing.
For this reason, it is necessary to develop a package having high reliability by improving light speed and the distribution of luminous intensity through the improvement of the secondary characteristics.
In order to improve light speed and distribution of luminous intensity and to manufacture a package having high reliability, an LED chip is bonded to a flat ceramic substrate having superior thermal characteristics and phosphors for manufacturing a white light source are uniformly applied to upper and side surfaces, i.e., light emitting surfaces of the LED chip using a chip label coating (CLC) method or the like.
Here, in a case in which the thickness of the applied phosphors is large, light conversion efficiency is reduced. Typically, light speed is lowered by 1% with respect to a phosphor thickness of 10 μm.
Furthermore, in a case in which the phosphor thickness is not entirely uniform, color deviation in light emitted from the LED chip occurs, resulting in a reduction of product reliability. Accordingly, a highly advanced phosphor applying technique is required, thereby resulting in a low yield, and thus product manufacturing time and costs are increased.